I just tried everything you said on my machine and it worked.
try following things:
1: make sure you use recent rpm version. In my case it is 4.9
2: do not download rpm and execute "rpm -i" from /usr/src. could be a problem with permissions.
3: make sure you use sudo
4: check permission of /home/chroot/var/lib/rpm. it should be 755
Good luck !!